Air spring



Nov. 20, 1928.

R. L. GRUSS AIR SPRING Filed Sept. 10, 1924 nz 'entn Raymond L UPU/S5.

Patented Nov. 20, 1928.

UNITED STATES PATENT OFFICE.v

RAYMOND L. GRUSS, OF SAN FRANCISCO, CALIFORNIA, ASSIGNOR, BY MESNE ASSIGN- MENTS, TO GRUSS AIR SPRING COMPANY OF AMERICA, OF SAN FRANCISCO, CALI- FORNIA, A CORPORATION OF CALIFORNIA.

AIR SPRING.

Application filed September 10, 1924. Serial No. 736,883.

This invention relates to cushioningdevices, shock absorbers and the like, and more particularly to the types which employ air as a cushioning medium and are known as air springs. l

The object of the present invention is to generally improve and simplify the construe tion and operation of air springs of the character described; to provide a spring which will efliciently cushion ordinary road shocks and which will also check rebound movements; to provide a piston structure which will reduce wear on the cup-leathers or other packing employed to a minimum; to provide a piston and packing structure which will re duce leakage of the sealing oil to a large extent, and further, to provide means for automatically returning the maj or portion of such sealing oil as may leak or escape by the piston structure.

One form which my invention may assume is exemplified in the following description and illustrated in the accompanying drawings., in which- Fig. 1 is a central vertical longitudinal section of the air spring.

Fig. 2 is a similar section showing u modii lied form of piston structure.

Referring to the drawings in detail, and particularly to Fig. 1, A indicates .in lgeneral a bottle or cylinder which issecured in a lower cylindrical casing B. The bottle may be constructed of seamless steel tubing or the like7 while the casing B may be constructed of cast-iron, theV bottle and the casing being joined ror secured with relation to each other by means of a threaded connection as at 2. The inner surface of the casing B is provided with a pad 3 and it is secured to the forward end of a. vehicle frame, such as indicated by dotted lines at 4, by means of an intermediate plate 5 secured to the pad by means of bolts 6.

The cylinder is divided into three compertinents, generally indicated at 7, 8 and 9. The compartments 8 and 9 are of uniform diameter, while the compartment 7 is slightly smaller. The upper end of the cylinder is closed by means of a rounded head member 10 and an inflating valve 11 is placed in the upper end thereof to permit air under pressure to be introduced.

Division of the cylinder or bottle A into kmember 21.

three chambers is accomplished by the use of two pistons generally indicated at 12 and 13. These pistons arecarried by a rod 14, which is connected to thesprings of a vehicle indicated by dotted vlines at 15 in any suitable manner; the lower end of the rod as shown at 16. The lower end of the cylindrical casing B is closed by means of a head member 17. A bearing 18 is formed centrally of the head member and a bearing bushing 19 extends therethrough. The rod 14 passes through the head and the bushing, and is guided and supported thereby. The piston 12 consists of an upwardly turned cup leather and it is secured to the rod 14 by means of a plate and a nut 20. The upper end of the rod 14 is shouldered, as shown, to form a support for a cup-shaped This member extends downwardly eXteriorly over the bushing 19 and it terminates in a pair of annular shoulders such as indicatedat 22 and 23, these shoulders forming a seat for a. downwardly turned cup leather 24 and an upwardly turned cup leather 25, the cup leathers 24 and 25 constituting the piston 13. The upper cup leather 25 is separated from the cup leather 24 by means of a central disk 26 and it is secured on the disk 26 by means of a spacing sleeve 27. The upper end of this sleeve is enlarged or expanded, as shown at 28, and as such forms an annular bearing contact with the interior surface of the cylinder 7, thereby relieving the cup leather of the upper piston from any side4 thrust or wear.

rlhe cup-shapedmember 21, which terminates in the lower annular shoulders y22 and 23, also serves as a bearing member to relieve the lower cup leathers 24 and 25 of side thrust and wear; that is, the lower portion 23 engages the inner surface of the cylinder chambers 8 and 9 and as such takes ofl" all wear at this point. The pistons are furthermore guided by means of the bushing 19, as this not only guides the rod 14 but also the cupshaped sleeve 21 and the spacing sleeve 27.

In actual practice, with the parts assembled as shown in Fig. 1 and mounted on an automobile, it will be understood that the upper cylinder 7 is partially filled with a heavy lubricating oil or grease such as indicated at 30. This grease or oil forms a seal above the pistons 12 and thereby permits the introducfor instance, by forking' eel tion of air under pressure through the valve 11, the air thus admitted having a sufficient pressure to cushion or sustain the load im posed on the spring 15. The sealing oil sometimes gets fairly thin, through heat and friction, and has a slight tendency to leak by the cup-leather 12. Any such leakage or escape of the oil will permit the oil to drain into the intermediate cylinder chamber 8. It is here caught by the upturned cup-leather 25 and cannot readily escape. Any oil escaping by the upper piston will gradually accumulate in the chamber S and it will be automatically returned to the upper cylinder chamber 7 when a sufficient amount of oil is collected; that is, the cylinder chamber 8 presents two chambers of varying areas. The lowermost position assumed by the pistons 12 and 13 determines the largest capacity of the cylinder chamber 8, but any outward movement of the pistons reduces this capacity, due to the differential action between the chambers of varying diameters. In other words leakage oil accumulating in the chamber 8 will be forced back into theupper chamber 7 during upward movement of the pistons, as the reduced area will produce suc-h a pressure as to force the oil upwardly by the upturned cup leather' of the upper piston and it is thus automatically returned from time to time to the upper cylinder chamber 7 where it will continue to perform its function. An eX- ceedingly small amount of oil will, of course, in time escape past the cup-leathers 24 and 25. Such oil will accumulate in the lower chamloer 9 and it may take months before a suflicient amount has collected to warrent its removal. This is accomplished by merely opening the plug 81 so that the oil may be drained off; that is, any excess accumulation of oil in the lower chamber 9 would be detrimental as it would hydraulically lock the pistons against movement, and it should for this reason be removed from time to time. The oil cannot escape from the lower chamber 9, as it would have to rise up over the upper edge of the bushing 19 and then escape downwardly between the bushing and the rod 14. Such escape of the oil is very unlikely and it might therefore be stated that the spring is, practically speaking, leak-proof as far as oil is concerned and as such will not'be mussed up 'with dust accumulating on surfaces covered with oil by leakage and so on.

The lower chamber 9 does not only serve the function of a trap for the accumulation of any oil which may finally escape by the upper and lower pistons, but it also serves the function of a compression chamber to check rebound movements. Rebound movement will cause upward movement of the cylinders and downward movement of the pistons. Air contained in the cylinder chamber 9 will thus be placed under compression and rebound movements will accordingly be checked. Ordinary road shocks are cushioned by the air in the upper Vcy-linder 7, as this compresses and expands in proportion to the road shocks encountered. n

The structure shown is exceedingly simple; it is compact and rigid in construction; ample bearing surfaces are provided to take care of all side thrust and st ainsg the packing medium, to-wit, the cup-leathers employed are relieved of all side thrust by the bearing bushing 19 and the piston extensions 23 and 28 and as such are only subject to naturai wear caused by reciprocal motion. yThe life of the springs should accordingly be materially increased and leakage of sealing oil should be reduced to a minimum. All parts should be amply lubricated as oil cannot escape, except by drainage through the plug B1, and as all parts are closed to the atmos-v phere it is obvious that dust and grit cannot enter and do damage.

The structure shown in Fig. 2 functions in a manner identi :al to that described in lig. l. The only difference between the two structures is caused by the elimination of the cupshaped sleeve 21 and the spacing sleeve 27. rlhese are done away with by forming shoulders on the rod indicated at 14a, the shoulders v being shown at d() and 41. A collar 42, seated on the upper shoulder 4.1, serves as a bearing and guide for the upper end of the rod 14;a and it also serves as a seat andsupport for the upper cup-leather.V The lower collar at) forms a seat for a bearing member aand this in turn forms aV seat for the cup-leathers indicated at lli and 45, these cup leathers, together with the bearing vring 43, being secured in position byI means of a nut a6. The bushing 19 is not entirely eliminated in this instance, but it is ,materially reduced in length as shown at 19.

l/lllhile certain features of the present invention are more or less specifically illustrated, I wish it understood that various changes in form and proportion may be resorted to within the scope of the appended claims. I'similarly wish it understood that the materials and finish of the several parts employed may be such as the'experience and judgment of the manufacturer may dictate or various usesv may demand.

Having thus described my invention, what I claim and desire to secure by Letters Patent is- 1. An air spring of the character described comprising an elongated cylinder divided into upper and lower sections of varying diameter' and the upper section presenting the smallest diameter, a head forming a closure for the upper cylinder section, a piston rod extending through the lower cylinder section and into the upper section, said rod being of smaller diameter than the upper cylinder section, a piston on the upper end ofthe rod les' and operating within the upper' section of thecylinder only, a second piston on the rod and operating in the lower cylinder section only, ai upwardly turned cup-leather carried by r piston, a pair of cup-leathers cartie lower piston, said cup-leathers -'e\'ersed so that one extends upwardly ension on the upperI piston forming a bearter the upper cup-leather to relieve the saine ot' all side thrusty and a inetallic annu- .r hearing extension on the lower piston to relier 4 the lower pair of cup-leathers of side hr u: r.

2. in air spring of' the character described luprising an elongated cylinder divided o upper and lower sections of varying di- :uueter and the upper section presenting the smallest diameter, a head forming a closure il'or the upper cylinder section, a piston rod elite-riding through the lower cylinder section and into the upper section, said rod being of smaller diameter' than the upper cylinder section, a piston on the upper end of the rod and operating within the upper section ot the cylinder only, a second piston on the rod and operating in the lo-wer cylinder section only. an upwardly turned cup-leather earrred hy vthe upper piston, a pair oi2 cup-leathe.; carrie( hy the lower piston, said cupleathers being reversed so that one extends upwardl),rr and one downwardly, a inetallic annular extension onthe upper piston forini g a. hearing for the upper cup-leather to relieve the saine ot all side thrust, a metallic annular bearing extension on the lower piston to relieve the lower pair of cup-leathers ot' side thrust and a bushing carried by the cylinder, said bushing forming a hearing and guide tor the piston rod.

23. An air spring of the character described ce" prising an elongated cylinder divided to upper and lower sections ot Varying dianleter and the upper section presenting the smallest diameter, a head forming a closure for the upper cylinder section, a piston rod extending through the lower cylinder section and into the upper section, said rod loeiug et sn'ialler diameter' than the upper cylinder section, a piston on the upper end ot' the rod and operating within the upper secone downwardly, a nietallic annular exl tion of the cylinder only, a second piston on the rod and operating in the lower cylinder section only, a head ineinher on the lower end of the cylinder, and an elongatedl hearing Abushingtherein through which the piston rod extends, said lower head n'ieniher forming a compression chainher in the lower end ot the cylinder to check recoil nioreinentx An air spring of the character described comprising an elongated cylinder divided into upper and lower sections of `varying diameter and the upper section presenting the smallest diaineter, a head orniing a closure for the upper cylinder section, a piston rod extending through the lower cylinder section and into the upper section, a piston on the upper end of the rod and operating within the upper section of the cylinder' only, a second piston on the rod and operatingl in the lower cylinder section only, and a bushing` secured within the cylinder and extending upwardly therein to the upper section of the cylinder, said bushing ori'ning aV hearing and guido 'for the piston rod and relieving the upper and lower pistons or" thrust.

An air spring` ot the character described` comprising an Y elongated cylinder divided into upper and lower sections of varying dianieter and the upper section presenting the smallest diameter, a headfforining a closure for the upper cylinder section, a. piston rod extending through the lower cylinder section and into the upper section., said rod heing oi slnaller dianieter than the upper cylinder section, a piston on the upper end of the rod and operating within the upper section of the cylinder only, a secon(L piston on the rod and operating in the lower cylinder section only,lcupleather packing n'ieinhers ou each piston, metallic hearing sections on each piston and engaging the respective cylinder hores, said bearing sections relieving the cup-leather packings of side thrust, and

an elono'ated hushino` secured to the lower cylinder' head, said bushing torining a guide and hearing for the piston rod and absorbH ing all side thrusts transniit-ted thereto, said bushing nieinber also relieving the pistons ot side thrust.

RAYMOND L. GRUSS. 

